V4L/DVB (7035): drivers/media/common: Add missing video_device_release

Video_device_alloc returns the result of a kzalloc. In this case, the
value is stored in a local variable which is not copied elsewhere before
the point of the error return (video_register_device does not save its
first argument anywhere if it returns a negative value). Thus, a
video_device_release it needed before the error return.

The problem was found using the following semantic match.
(http://www.emn.fr/x-info/coccinelle/)

// <smpl>
@@
type T,T1,T2;
identifier E;
statement S;
expression x1,x2,x3;
int ret;
@@

T E;
...
* E = video_device_alloc(...);
if (E == NULL) S
... when != video_device_release(...,(T1)E,...)
when != if (E != NULL) { ... video_device_release(...,(T1)E,...); ...}
when != x1 = (T1)E
when != E = x3;
when any
if (...) {
... when != video_device_release(...,(T2)E,...)
when != if (E != NULL) { ... video_device_release(...,(T2)E,...); ...}
when != x2 = (T2)E
(
* return;
|
* return ret;
)
}
// </smpl>

Signed-off-by: Julia Lawall <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
CC: Oliver Endriss <[e-mail]>
CC: Michael Hunold <[e-mail]>
Signed-off-by: Mauro Carvalho Chehab <[e-mail]>

drivers/media/common/saa7146_fops.c

···
 	// fixme: -1 should be an insmod parameter *for the extension* (like "video_nr");
 	if (video_register_device(vfd, type, -1) < 0) {
 		ERR(("cannot register v4l2 device. skipping.\n"));
+		video_device_release(vfd);
 		return -1;
 	}